Refactor/errors (#210)

Author: ka-myl

CHANGELOG.md

@@ -5,6 +5,12 @@ See updating [Changelog example here](https://keepachangelog.com/en/1.0.0/)
 
 ## [Unreleased]
 
+### Changed
+- errors: all service method now return `Problem` type in case of errors (*BREAKING CHANGE*)
+
+### Removed
+- errors: `Error` type was removed (*BREAKING CHANGE*)
+
 ## [5.4.0]
 
 ### Added

README.md

@@ -70,9 +70,14 @@ _, err := svc.GetAccount(context.Background())
 // Handle errors in general
 if (err != nil) {
 	// Handle service errors specifically
-	if serviceError, ok := err.(*upcloud.Error); ok {
-		fmt.Println(serviceError.ErrorCode)
-		fmt.Println(serviceError.ErrorMessage)
+	if serviceError, ok := err.(*upcloud.Problem); ok {
+		fmt.Println(serviceError.Type)
+		fmt.Println(serviceError.Title)
+		fmt.Prinln(serviceError.Status)
+		// You can use ErrorCode() method to compare error against a set of ErrCode constants
+		if serviceError.ErrorCode == upcloud.ErrCodeAuthenticationFailed {
+			// ...
+		}
 	}
 }
 ````

upcloud/error.go

@@ -2,6 +2,7 @@ package upcloud
 
 import (
 	"fmt"
+	"net/url"
 	"strings"
 )
 
@@ -14,12 +15,19 @@ type Problem struct {
 	// InvalidParams if set, is a list of ProblemInvalidParam describing a specific part(s) of the request
 	// that caused the problem
 	InvalidParams []ProblemInvalidParam `json:"invalid_params,omitempty"`
-	// CorrelationID is an unique string that identifies the request that caused the problem
+	// CorrelationID is a unique string that identifies the request that caused the problem
+	// Please note that it is not always available
 	CorrelationID string `json:"correlation_id,omitempty"`
 	// HTTP Status code
 	Status int `json:"status"`
 }
 
+// ProblemInvalidParam is a type describing extra information in the Problem type's InvalidParams field.
+type ProblemInvalidParam struct {
+	Name   string `json:"name"`
+	Reason string `json:"reason"`
+}
+
 func (p *Problem) Error() string {
 	var sb strings.Builder
 	_, _ = fmt.Fprintf(&sb, "error: message=%q, type=%q", p.Title, p.Type)
@@ -34,8 +42,15 @@ func (p *Problem) Error() string {
 	return sb.String()
 }
 
-// ProblemInvalidParam is a type describing extra information in the Problem type's InvalidParams field.
-type ProblemInvalidParam struct {
-	Name   string `json:"name"`
-	Reason string `json:"reason"`
+// ErrorCode returns a short string that identifies the error; it should be used for programmatic comparisons
+func (p *Problem) ErrorCode() string {
+	// First check if the type is a URL.
+	// If it is - we need to extract meaningful fragment from it for comparison purposes
+	// If it isn't - we can just return the value of `Type` field
+	parsedURL, err := url.Parse(p.Type)
+	if err != nil || parsedURL.Scheme == "" || parsedURL.Host == "" {
+		return p.Type
+	}
+
+	return strings.Replace(parsedURL.Fragment, "ERROR_", "", 1)
 }

upcloud/error_codes.go

@@ -7,7 +7,7 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestProblem(t *testing.T) {
+func TestProblemUnmarshal(t *testing.T) {
 	p := Problem{}
 	err := json.Unmarshal([]byte(`
 	{
@@ -31,3 +31,24 @@ func TestProblem(t *testing.T) {
 	assert.Equal(t, "Backend doesn't exist.", p.InvalidParams[0].Reason)
 	assert.Equal(t, "default_backend", p.InvalidParams[0].Name)
 }
+
+func TestProblemErrorCodes(t *testing.T) {
+	p := Problem{
+		Type: "https://api.upcloud.com/1.3/errors#ERROR_RESOURCE_ALREADY_EXISTS",
+	}
+	assert.Equal(t, ErrCodeResourceAlreadyExists, p.ErrorCode())
+	assert.NotEqual(t, ErrCodeAuthenticationFailed, p.ErrorCode())
+
+	p.Type = "https://api.upcloud.com/1.3/errors#ERROR_AUTHENTICATION_FAILED"
+	assert.Equal(t, ErrCodeAuthenticationFailed, p.ErrorCode())
+
+	p.Type = "http://api.upcloud.com/1.3/errors#ERROR_INVALID_REQUEST"
+	assert.Equal(t, ErrCodeInvalidRequest, p.ErrorCode())
+
+	p.Type = "GROUP_NOT_FOUND"
+	assert.Equal(t, ErrCodeGroupNotFound, p.ErrorCode())
+
+	p.Type = "SERVER_NOT_FOUND"
+	assert.Equal(t, ErrCodeServerNotFound, p.ErrorCode())
+	assert.NotEqual(t, "SOME_RANDOM_STRING", p.ErrorCode())
+}

upcloud/error_test.go

@@ -10,7 +10,7 @@ interactions:
       Content-Type:
       - application/json
       User-Agent:
-      - upcloud-go-api/4.9.0
+      - upcloud-go-api/5.4.0
     url: https://api.upcloud.com/1.3/server/invalid/start
     method: POST
   response:
@@ -27,7 +27,7 @@ interactions:
       Content-Type:
       - application/json; charset=UTF-8
       Date:
-      - Mon, 24 Oct 2022 11:06:08 GMT
+      - Tue, 07 Feb 2023 08:05:53 GMT
       Server:
       - Apache
       Strict-Transport-Security:

upcloud/problem.go

@@ -288,15 +288,15 @@ func TestService_GetManagedDatabaseConnections(t *testing.T) {
 			Terminate: true,
 		})
 		assert.Error(t, err)
-		assert.True(t, strings.HasPrefix(err.(*upcloud.Error).ErrorMessage, "Must provide a connection"))
+		assert.True(t, strings.HasPrefix(err.(*upcloud.Problem).Title, "Must provide a connection"))
 
 		err = svc.CancelManagedDatabaseConnection(ctx, &request.CancelManagedDatabaseConnection{
 			UUID:      serviceDetails.UUID,
 			Pid:       0,
 			Terminate: false,
 		})
 		assert.Error(t, err)
-		assert.True(t, strings.HasPrefix(err.(*upcloud.Error).ErrorMessage, "Must provide a connection"))
+		assert.True(t, strings.HasPrefix(err.(*upcloud.Problem).Title, "Must provide a connection"))
 	})
 }
 

upcloud/problem_test.go

@@ -223,7 +223,7 @@ func TestErrorHandling(t *testing.T) {
 		})
 
 		// Check that the correct error type is returned
-		expectedErrorType := "*upcloud.Error"
+		expectedErrorType := "*upcloud.Problem"
 		actualErrorType := reflect.TypeOf(err).String()
 
 		if actualErrorType != expectedErrorType {